pop3.cpp

pop3接收邮件通信程序

  //if we haven't executed the UIDL command then do it now
  if (!m_bUIDLRetrieved)
    bSuccess = UIDL();

  //nMsg must be in the correct range
  ASSERT((nMsg > 0) && (nMsg <= m_msgIDs.GetSize()));

  //retrieve the size from the message size array
  sID = m_msgIDs.GetAt(nMsg - 1);

  return bSuccess;
}

BOOL CPop3Connection::List()
{
  //Must be connected to perform a "LIST"
  ASSERT(m_bConnected);

  //if we haven't executed the STAT command then do it now
  int nNumberOfMails = m_nNumberOfMails;
  int nTotalMailSize;
  if (!m_bStatRetrieved)
  {
    if (!Statistics(nNumberOfMails, nTotalMailSize))
      return FALSE;
    else
      m_bStatRetrieved = TRUE;
  }

  //Send the LIST command
  char sBuf[10];
	strcpy(sBuf, "LIST\r\n");
  int nCmdLength = strlen(sBuf);
	if (!m_Pop.Send(sBuf, nCmdLength))
  {
    TRACE(_T("Failed to send the LIST command to the POP3 server\n"));
    return FALSE;
  }
  //And check the response
	m_bListRetrieved = ReadListResponse(nNumberOfMails);
  return m_bListRetrieved;
}

BOOL CPop3Connection::UIDL()
{
  //Must be connected to perform a "UIDL"
  ASSERT(m_bConnected);

  //if we haven't executed the STAT command then do it now
  int nNumberOfMails = m_nNumberOfMails;
  int nTotalMailSize;
  if (!m_bStatRetrieved)
  {
    if (!Statistics(nNumberOfMails, nTotalMailSize))
      return FALSE;
    else
      m_bStatRetrieved = TRUE;
  }

  //Send the UIDL command
  char sBuf[10];
	strcpy(sBuf, "UIDL\r\n");
  int nCmdLength = strlen(sBuf);
	if (!m_Pop.Send(sBuf, nCmdLength))
  {
    TRACE(_T("Failed to send the UIDL command to the POP3 server\n"));
    return FALSE;
  }
  //And check the response
	m_bUIDLRetrieved = ReadUIDLResponse(nNumberOfMails);
  return m_bUIDLRetrieved;
}

BOOL CPop3Connection::Reset()
{
  //Must be connected to perform a "RSET"
  ASSERT(m_bConnected);

  //Send the RSET command
	char sBuf[10];
 	strcpy(sBuf, "RSET\r\n");
  int nCmdLength = strlen(sBuf);
	if (!m_Pop.Send(sBuf, nCmdLength))
  {
    TRACE(_T("Failed to send the RSET command to the POP3 server\n"));
    return FALSE;
  }

  //And check the command
	return ReadCommandResponse();
}

BOOL CPop3Connection::Noop()
{
  //Must be connected to perform a "NOOP"
  ASSERT(m_bConnected);

  //Send the NOOP command
	char sBuf[10];
 	strcpy(sBuf, "NOOP\r\n");
  int nCmdLength = strlen(sBuf);
	if (!m_Pop.Send(sBuf, nCmdLength))
  {
    TRACE(_T("Failed to send the NOOP command to the POP3 server\n"));
    return FALSE;
  }

  //And check the response
	return ReadCommandResponse();
}

BOOL CPop3Connection::Retrieve(int nMsg, CPop3Message& message)
{
  //Must be connected to retrieve a message
  ASSERT(m_bConnected);

  //work out the size of the message to retrieve
  DWORD dwSize;
  if (GetMessageSize(nMsg, dwSize))
  {
    //Send the RETR command
	  char sBuf[20];
	  sprintf(sBuf, "RETR %d\r\n", nMsg);	
    int nCmdLength = strlen(sBuf);
	  if (!m_Pop.Send(sBuf, nCmdLength))
    {
      TRACE(_T("Failed to send the RETR command to the POP3 server\n"));
      return FALSE;
    }
    
		//And check the command
	  return ReadReturnResponse(message, dwSize);
  }
  else
    return FALSE;
}

BOOL CPop3Connection::GetMessageHeader(int nMsg, CPop3Message& message)
{
  // Must be connected to retrieve a message
  ASSERT(m_bConnected);

  // make sure the message actually exists
  DWORD dwSize;
  if (GetMessageSize(nMsg, dwSize))
  {
    // Send the TOP command
    char sBuf[16];
    sprintf(sBuf, "TOP %d 0\r\n", nMsg);
    int nCmdLength = strlen(sBuf);
    if (!m_Pop.Send(sBuf, nCmdLength))
    {
      TRACE(_T("Failed to send the TOP command to the POP3 server\n"));
      return FALSE;
    }

    // And check the command
    return ReadReturnResponse(message, dwSize);
  }
  else
    return FALSE;
}

BOOL CPop3Connection::ReadCommandResponse()
{
  LPSTR pszOverFlowBuffer = NULL;
  char sBuf[1000];
  BOOL bSuccess = ReadResponse(sBuf, 1000, "\r\n", &pszOverFlowBuffer);
  if (pszOverFlowBuffer)
    delete [] pszOverFlowBuffer;
  
  return bSuccess;
}

LPSTR CPop3Connection::GetFirstCharInResponse(LPSTR pszData) const
{
  while ((*pszData != '\n') && *pszData)
    ++pszData;

  //skip over the "\n" onto the next line
  if (*pszData)
    ++pszData;

  return pszData;
}

BOOL CPop3Connection::ReadResponse(LPSTR pszBuffer, int nInitialBufSize, LPSTR pszTerminator, LPSTR* ppszOverFlowBuffer, int nGrowBy)
{
  ASSERT(ppszOverFlowBuffer);          //Must have a valid string pointer
  ASSERT(*ppszOverFlowBuffer == NULL); //Initially it must point to a NULL string

  //must have been created first
  ASSERT(m_bConnected);

  //The local variables which will receive the data
  LPSTR pszRecvBuffer = pszBuffer;
  int nBufSize = nInitialBufSize;
  
  //retrieve the reponse using until we
	//get the terminator or a timeout occurs
	BOOL bFoundTerminator = FALSE;
	int nReceived = 0;
	DWORD dwStartTicks = ::GetTickCount();
	while (!bFoundTerminator)
	{
		//Has the timeout occured
		if ((::GetTickCount() - dwStartTicks) >	m_dwTimeout)
		{
		  pszRecvBuffer[nReceived] = '\0';
      SetLastError(WSAETIMEDOUT);
      m_sLastCommandResponse = pszRecvBuffer; //Hive away the last command reponse
			return FALSE;
		}

    //check the socket for readability
    BOOL bReadible;
    if (!m_Pop.IsReadible(bReadible))
    {
	    pszRecvBuffer[nReceived] = '\0';
			m_sLastCommandResponse = pszRecvBuffer; //Hive away the last command reponse
			return FALSE;
    }
    else if (!bReadible) //no data to receive, just loop around
    {
      Sleep(250); //Sleep for a while before we loop around again
      continue;
    }

		//receive the data from the socket
    int nBufRemaining = nBufSize-nReceived-1; //Allows allow one space for the NULL terminator
    if (nBufRemaining<0)
      nBufRemaining = 0;
	  int nData = m_Pop.Receive(pszRecvBuffer+nReceived, nBufRemaining);

    //Reset the idle timeout if data was received
    if (nData)
    {
			dwStartTicks = ::GetTickCount();

      //Increment the count of data received
		  nReceived += nData;							   
    }

    //If an error occurred receiving the data
		if (nData == SOCKET_ERROR)
		{
      //NULL terminate the data received
      if (pszRecvBuffer)
		    pszBuffer[nReceived] = '\0';

      m_sLastCommandResponse = pszRecvBuffer; //Hive away the last command reponse
		  return FALSE; 
		}
		else
		{
      //NULL terminate the data received
      if (pszRecvBuffer)
		    pszRecvBuffer[nReceived] = '\0';

      if (nBufRemaining-nData == 0) //No space left in the current buffer
      {
        //Allocate the new receive buffer
        nBufSize += nGrowBy; //Grow the buffer by the specified amount
        LPSTR pszNewBuf = new char[nBufSize];

        //copy the old contents over to the new buffer and assign 
        //the new buffer to the local variable used for retreiving 
        //from the socket
        if (pszRecvBuffer)
          strcpy(pszNewBuf, pszRecvBuffer);
        pszRecvBuffer = pszNewBuf;

        //delete the old buffer if it was allocated
        if (*ppszOverFlowBuffer)
          delete [] *ppszOverFlowBuffer;
        
        //Remember the overflow buffer for the next time around
        *ppszOverFlowBuffer = pszNewBuf;        
      }
		}

    //Check to see if the terminator character(s) have been found
		bFoundTerminator = (strstr(pszRecvBuffer, pszTerminator) != NULL);
	}

	//Remove the terminator from the response data
  pszRecvBuffer[nReceived - strlen(pszTerminator)] = '\0';

  //determine if the response is an error
	BOOL bSuccess = (strnicmp(pszRecvBuffer,"+OK", 3) == 0);

  if (!bSuccess)
  {
    SetLastError(WSAEPROTONOSUPPORT);
    m_sLastCommandResponse = pszRecvBuffer; //Hive away the last command reponse
  }

  return bSuccess;
}

BOOL CPop3Connection::ReadReturnResponse(CPop3Message& message, DWORD dwSize)
{
  //Must be connected to perform a "RETR"
  ASSERT(m_bConnected);

  //Retrieve the message body
  LPSTR pszOverFlowBuffer = NULL;
  int nSize = dwSize + 100;
  char* sBuf = new char[nSize];
  char* sMessageBuf = sBuf;
  if (!ReadResponse(sBuf, nSize, "\r\n.\r\n", &pszOverFlowBuffer, 32000))
	{
    delete [] sBuf;
    if (pszOverFlowBuffer)
      delete [] pszOverFlowBuffer;

		TRACE(_T("Error retrieving the RETR response"));
		return FALSE;
	}
  if (pszOverFlowBuffer)
    sMessageBuf = pszOverFlowBuffer;

  //determine if the response is an error
  if (strnicmp(sMessageBuf,"+OK", 3) != 0)
	{
    delete [] sBuf;
    if (pszOverFlowBuffer)
      delete [] pszOverFlowBuffer;

    SetLastError(WSAEPROTONOSUPPORT);
		TRACE(_T("POP3 server did not respond correctly to the RETR response\n"));
		return FALSE;
	}
	else
	{  
    //remove the first line which contains the +OK from the message
    char* pszFirst = GetFirstCharInResponse(sMessageBuf);
		VERIFY(pszFirst);

    //transfer the message contents to the message class
    int nMessageSize = sMessageBuf - pszFirst + strlen(sMessageBuf);

    // Do we already have memory allocated? If so, destroy it!
  	if (message.m_pszMessage)
  	{
  	  delete [] message.m_pszMessage;
  	  message.m_pszMessage = NULL;
    }

    message.m_pszMessage = new char[nMessageSize + 1];
    memcpy(message.m_pszMessage, pszFirst, nMessageSize);
    message.m_pszMessage[nMessageSize] = '\0';
	}
  delete [] sBuf;
  if (pszOverFlowBuffer)
    delete [] pszOverFlowBuffer;

  return TRUE; 
}

BOOL CPop3Connection::ReadListResponse(int nNumberOfMails)
{
  //Must be connected to perform a "LIST"
  ASSERT(m_bConnected);

  //retrieve the reponse
  LPSTR pszOverFlowBuffer = NULL;
  int nSize = 14 * nNumberOfMails + 100;
  char* sBuf = new char[nSize];
  char* sMessageBuf = sBuf;
  if (!ReadResponse(sBuf, nSize, "\r\n.\r\n", &pszOverFlowBuffer))
	{
    delete [] sBuf;
    if (pszOverFlowBuffer)
      delete [] pszOverFlowBuffer;

		TRACE(_T("Error retrieving the LIST response from the POP3 server"));
		return FALSE;
	}
  if (pszOverFlowBuffer)
    sMessageBuf = pszOverFlowBuffer;

  //determine if the response is an error
  if (strnicmp(sMessageBuf,"+OK", 3) != 0)
	{
    delete [] sBuf;
    if (pszOverFlowBuffer)
      delete [] pszOverFlowBuffer;

    SetLastError(WSAEPROTONOSUPPORT);
		TRACE(_T("POP3 server did not respond correctly to the LIST response\n"));
		return FALSE;
	}
	else
	{  
    //Retrieve the message sizes and put them
    //into the m_msgSizes array
    m_msgSizes.RemoveAll();
    m_msgSizes.SetSize(0, nNumberOfMails);

    //then parse the LIST response
		char* pszSize = GetFirstCharInResponse(sMessageBuf);
		VERIFY(pszSize);
		for (; *pszSize != '.'; pszSize++)
			if (*pszSize == '\t' || *pszSize == ' ')
				m_msgSizes.Add(atoi(pszSize));
	}
  delete [] sBuf;
  if (pszOverFlowBuffer)
    delete [] pszOverFlowBuffer;

  return TRUE; 
}

BOOL CPop3Connection::ReadUIDLResponse(int nNumberOfMails)
{
  //Must be connected to perform a "LIST"
  ASSERT(m_bConnected);

  //retrieve the reponse
  LPSTR pszOverFlowBuffer = NULL;
  int nSize = 14 * nNumberOfMails + 100;
  char* sBuf = new char[nSize];
  char* sMessageBuf = sBuf;
  if (!ReadResponse(sBuf, nSize, "\r\n.\r\n", &pszOverFlowBuffer))
	{
    delete [] sBuf;
    if (pszOverFlowBuffer)
      delete [] pszOverFlowBuffer;

		TRACE(_T("Error retrieving the UIDL response from the POP3 server"));
		return FALSE;
	}
  if (pszOverFlowBuffer)
    sMessageBuf = pszOverFlowBuffer;

  //determine if the response is an error
  if (strnicmp(sMessageBuf,"+OK", 3) != 0)
	{
    delete [] sBuf;
    if (pszOverFlowBuffer)
      delete [] pszOverFlowBuffer;

    SetLastError(WSAEPROTONOSUPPORT);
		TRACE(_T("POP3 server did not respond correctly to the UIDL response\n"));
		return FALSE;
	}
	else
	{  
    //Retrieve the message ID's and put them
    //into the m_msgIDs array
    m_msgIDs.RemoveAll();
    m_msgIDs.SetSize(0, nNumberOfMails);

    //then parse the UIDL response
		char* pszSize = GetFirstCharInResponse(sMessageBuf);
		VERIFY(pszSize);
		for (; *pszSize != '.'; pszSize++)
    {
      char* pszBegin = pszSize;
      while (*pszSize != '\n' && *pszSize != '.')
      {
        ++pszSize;
      }
      if (*pszSize == '.')
        continue;

      char sMsg[15];
      char sID[1000];
      *pszSize = '\0';
      sscanf(pszBegin, "%s %s", sMsg, sID);

      m_msgIDs.Add(CString(sID));
    }
	}
  delete [] sBuf;
  if (pszOverFlowBuffer)
    delete [] pszOverFlowBuffer;

  return TRUE; 
}

BOOL CPop3Connection::ReadStatResponse(int& nNumberOfMails, int& nTotalMailSize)
{
  //Must be connected to perform a "STAT"
  ASSERT(m_bConnected);

  //retrieve the reponse
  LPSTR pszOverFlowBuffer = NULL;
  char sBuf[100];
  char* sMessageBuf = sBuf;
  if (!ReadResponse(sBuf, 100, "\r\n", &pszOverFlowBuffer))
  {
    if (pszOverFlowBuffer)
      delete [] pszOverFlowBuffer;

		TRACE(_T("Error retrieving the STAT response from the POP3 server"));
		return FALSE;
  }
  if (pszOverFlowBuffer)
    sMessageBuf = pszOverFlowBuffer;

  //determine if the response is an error
  if (strncmp(sMessageBuf,"+OK", 3) != 0)
	{
		TRACE(_T("POP3 server did not respond correctly to the STAT response\n"));
		return FALSE;
	}
	else
	{                                          
    //Parse out the Number of Mails and Total mail size values
		BOOL bGetNumber = TRUE;
		for (char* pszNum=sMessageBuf; *pszNum!='\0'; pszNum++)
		{
			if (*pszNum=='\t' || *pszNum==' ')
			{						
				if (bGetNumber)
				{
					nNumberOfMails = atoi(pszNum);
          m_nNumberOfMails = nNumberOfMails;
					bGetNumber = FALSE;
				}
				else
				{
					nTotalMailSize = atoi(pszNum);
					return TRUE;
				}
			}
		}
	}
  if (pszOverFlowBuffer)
    delete [] pszOverFlowBuffer;

  return FALSE; 
}